Thickening compositions containing xanthomonas gum and hydroxyalkyl ether of guar gum

ABSTRACT

A blend of xanthomonas gum and hydroxyalkyl ether of guar gum which has unique thickening properties. The blend is particularly useful in printing paste and explosive slurries.

111M States Patent 1 Jordan 1 July 24, 1973 1 THICKENING COMPOSITIONS[56] References Cited CONTAINING XANTHOMONAS GUM AND UNITED STATESPATENTS HYDROXYALKYL ETHER 0F GUAR GUM 3,326,733 6/1967 Colegrove 149/44X [75] Inventor: Wesley A. Jordan, Minneapolis, 3,395,056 7/1968Bronstein.... 149/44 Minn. 3,465,675 9/1969 Bronstein.... 149/44 X3,658,607 4 1972 Cook et a]. 149/44 X [73] Assigneez General MlllSChemicals, Inc.,

Mmneapohs Primary Examiner-Stephen .1. L echert, Jr. [22] Filed: Oct. 8,1971 A ttorney-Anthony A. .Iuettner, Elizabeth Tweedy 21 Appl. No.2187,892

[57] ABSTRACT Cl A blend of xanthomonas gum and hydroxyalkyl ether149/76, 260/209 R, 117/165 of guar gum which has unique thickeningproperties. [51] Int. Cl C061) 15/00 The blend is particularly useful inprinting paste and ex- [58] Field of Search 149/44, 76, 60, 109; plosiveslurries.

5 Claims, No Drawings This invention relates to thickening compositions.More particularly, this invention relates to thickening compositionscomprising xanthomonas gum and hydroxyalkyl ether of guar gum andprinting paste and explosive slurries containing said thickeningcompositions.

Natural and synthetic gums have been used as thickeners for foods,coatings, paints, dyes, explosive slur ries, oilwell fluids and manyother applications. Thickeners impart viscosity to sols in which theyare incorporated. When there is no change in viscosity when shear forcethrough agitation is applied to the sol, the behavior of the thickeneris said to be Newtonian. A thickener is said to be plastic when theviscosity of the sol in a quiescent state is greater than when a shearforce is applied through agitation, the viscosity decreases as the shearforce applied increases, and the viscosity recovers immediately when themagnitude of shear force is decreased. Generally, when the so] is atrest, the molecules arrange themselves into a more or less stable form.In order to break this stable molecular arrangement and cause the so] toyield, the application of a shear force is necessary. The shear forcerequired to cause the sol to yield and flow is termed the gel strength.Once the gel strength of a plastic sol is overcome, the viscosity of thesol decreases as greater shear force is applied. Another property ofplastic sols is their viscosity differential. By viscosity differentialis meant the drop in viscosity between viscosities at low shear forceand at high shear force. This is a measure of the rate and extent ofthinning due to agitation. Still another property of plastic sols is therelationship betwen viscosity and thickener concentration. Sols, whichexhibit a large viscosity decrease as the concentration of thickenerdecreases, can be easily thinned by diluting with a solvent. Finally,the flow rate of the sol at any viscosity is important in manyapplications.

It is readily apparent that high gel strengths are desirable when othermaterials are to be suspended in the sol. This is true with productssuch as in paints and explosive slurries. It is also apparent thatplastic properties, namely a decrease in viscosity with agitation, isimportant when the suspended material is to be moved or deposited fromthe sol. For example, in the case of paint it is desirable to suspend asmuch pigment as possible in the sol and not have it settle duringstorage. When actually used, it is desirable that the paint thin outwith stirring, brushing or rolling so that the paint will spread onto asurface. It is further apparent that high viscosity differentials aredesirable to combine the greatest gel strength and viscosity, when thesol is at rest, with the greatest spreadability, when the so] isagitated. Finally, it is apparent that when the sol is to be removedafter the suspended material is deposited, a rapid decrease in viscosityas the sol is diluted is desirable.

Aqueous sols of xanthomonas gum are plastic in nature and exhibit highergel strengths than sols of other gums. Aqueous sols of hydroxyalkylether of guar are almost Newtonian and exhibit little or no gelstrength. Aqueous sols of the thickening compositions of the presentinvention are plastic in character. At certain concentrations of thethickening compositions in aqueous sols, the sols have higher gelstrengths than can be obtained from xanthomonas gum alone. At certainconcentrations, the aqueous sols containing the thickening compositionsexhibit greater viscosity differentials than do sols containingxanthomonas gum alone. In addition, the aqueous sols exhibit a greaterdrop in viscosity as the thickening composition concentration is reducedthan do aqueous sols of xanthomonas gum alone.

xanthomonas gum is one component in the thickening compositions of thepresent invention. Xanthomonas gum can be made by the fermentation ofcarbohydrate with bacteria of the genus xanthomonas. Representative ofthese bacteria are Xanthomonas campestris, Xanthamonas phaseoli,Xantlhomonas mulvacearn, Xanthomonas carotae, Xanthomonas translucens,Xanthomonas hederae and Xanthomonas papavericoli. The gum produced bythe bacteria Xanthomonas campestris is preferred for the purpose of thisinvention. The fermentation usually involves inoculating a fermentablebroth containing a carbohydrate, various minerals and a nitrogenyielding compound. A number of modifications in the fermentationprocedure and subsequent processing are commercially used. Due to thevariety of fermentation techniques and differences in processingoperation subsequent to fermentation, different production lots ofxanthomonas gum will have somewhat different solubility and viscosityproperties. Xanthomonas gum useful in the practice of the presentinvention are relatively hydratable xanthomonas gums. In general,xanthomonas gums having hydratability at 1 percent concentration byweight of about 1,800 to 3,500 centipoise in water and in an aqueoussolution containing 3 percent by weight potassium hydroxide are used.Preferably, xanthomonas gum having a hydratability in the above media ofabout 2,000 to 3,000 centipoise are used. The hydratability is measuredat a temperature of about 25 C.

The xanthomonas gum used in the blends of xanthomonas gum andhydroxypropyl guar gum discussed in detail below was made according tothe following procedure. In the first step the bacteria was grown on anagar slant. In the second step bacteria from the slant was used toinoculate two liter aliquots of a fermentable broth containing perliter: sucrose, 20 grams; Na HPOflZH O, 8 grams; NaH PO 1 gram; MgSO '7HO, 0.25 gram; and grams of cooked soy meal dispersion. The cooked soymeal suspension was made by agitating at rpm, 90 grams of soy meal in600 ml. of water at a temperature of 90C. for a period of 30 minutes andthen centrifuging and discarding the residue. The above broth wasallowed to ferment for a period of 31 hours at a temperature of about 28to 30C. In the third step the broth was used to inoculate a 15 literbatch containing the same broth composition. The broth of the third stepwas allowed to ferment for a period of 29 hours at a temperature ofabout 28 to 30C. The broth from the third step was used to inoculate al5,000 liter batch of broth having the composition per liter of broth,sucrose 20 grams; cooked soy meal dispersion, 6 grams; rapeseed oil,0.65 gram; sulfuric acid, 0.53 gram; MgSO '7I-l O, 0.25 gram; Na H-PO,-l2H O, 15 grams and tap water. The final batch was allowed toferment for a period of about 72 hours at a temperature of about 28 to30C. At the end of the final fermentation period the broth was steamsterilized to destroy all the viable microorganisms. The pH of the brothwas then adjusted to 7.9 by the addition of potassium hydroxide and thegum recovered from the broth by the addition of isopropyl alcohol.

The hydroxyalkyl ether of guar gum used in the thickening composition ofthe present invention can be made by reacting guar gum with alkyleneoxide in the presence of an alkaline catalyst. The alkylene oxide formsan ether linkage with a hydroxyl group of the guar gum. In guar gum eachsaccharide ring has an average of three hydroxyl groups with which thealkylene oxide can react. The degree of substitution of the hydroxyalkylether group is defined as oxirane equivalents'of alkylene oxide peranhydrohexose unit of guar gum. The degree of substitution generallyuseful in the practice of this invention is about 0.2 to 1.2 andpreferably about 0.8 to 0.9. I-Iydroxyalkyl ethers of guar gum that canbe used in the practice of this invention are those derived fromreacting an alkylene oxide containing two to four carbon atoms, namelyethylene oxide, propylene oxide and butylene oxide. 1,2-Butylene oxideis a common commercial chemical. 2,3-Butylene oxide is generally presentin crude mixtures with 1,2- Butylene oxide.

In order for the reaction between the guar gum and the alkylene oxide toproceed, the presence of an alkaline catalyst is necessary. Suchcatalysts are in general the alkali metal or alkaline earth metalhydroxides such as sodium, potassium or calcium hydroxide. Ammonia mayalso be used, as well as more complex basic catalysts such as benzyltrimethyl ammonium hydroxide. No special advantage, however, is obtainedby the use of more exotic basic or alkaline catalysts over the use ofsodium hydroxide which is commonly available.

Very small amounts of catalyst may be employed, as low as 0.05 percentbased on the weight of the guar gum. It is generally not necessary toexceed percent by weight of the guar gum, although larger amounts mightbe used. In general, about 2 percent to 3 percent catalyst by weight ofthe guar gum is employed.

The reaction can be conducted at room temperature or elevatedtemperatures. The temperature range in which the reaction is generallyconducted is about 17C. to'about 100C. While higher temperatures can beused, such as up to 125C., there is generally no advantage achieved.

The reaction can be conducted at atmospheric temperature, under reflux,or at elevated pressures in a closed reactor. The exact pressure is notcritical and while higher pressure may be employed, operation isnormally conducted at whatever pressure develops during the reaction.Generally such autogenous pressures will be on the order of from about30 to 125 p.s.i.g.

' The reaction may be conducted in the substantial absence of water orsolvent (no water added) although the efficiency of the reaction is verylow without the addition of watc -Accordingly, the reaction is generallyconducted in the presence of water to provide higher reactionefficiency. In the absence of other solvents, catalytic amounts of wateron the order of about 3 to 8 percent by weight based on the guar gum areemployed. These small amounts are generally used where highertemperatures and elevated pressures are employed, whereas larger amountsof water are used when lower tamperatures and atmospheric pressure areemployed. Further, other organic solvents either watermiscible orwater-immiscible organic solvents can be 1 employed. Illustrative ofsuch organic solvents are isopropanol (water-miscible) and heptane(waterimmiscible). Other unreactive organic solvents may be employedalthough the two mentioned are preferred. Such other organic solventsare the common aliphatic hydrocarbons having from five to ten carbonatoms which are commercially available such as heptane and hexane.Alcohols higher than methanol, those having from two to six carbonatoms, may be employed also such as t-butanol, the only requirementbeing that the solvent be substantially unreactive. Where higher waterlevels are employed, the water should be sufficient to swell the guargums slightly, thereby making the gum more reactive. When employed witha solvent, such as isopropanol or heptane, from about 10 to percentwater based on the weight of guar gum, is employed. The preferred amountof water is about 30 to 70 percent with the water-miscible solvents andabout 20 to 30 percent with the water-immiscible solvents.

Where organic solvents are employed, they are generally present in anamount up to eight times the amount of gum by weight, although largeramounts may be employed if desired. Generally, with watermisciblesolvents, an amount equal to one to three times the weight of gum isemployed. With waterimmiscible solvents, an amount of from three to fivetimes the weight of gum is generally employed. With the organicsolvents, the ratio by weight of water to organic solvent is preferablywithin the range of about 0.05 to 0.5. A range of 0.2 to 0.45 ispreferred withthe water-miscible organic solvents and from about 0.1 to0.2 is preferred with the water-immiscible organic solvents. In general,any unreactive organic solvent may be employed. With the lower ratios ofwater to organic solvent, the reaction is slower. With the higherratios, the recovery of product by filtration is slowed.

The thickening compositions of this invention can be made by dryblending xanthomonas gum and hydroxyalkyl ether of guar gum. The blendscontain about 5 to percent xanthomonas gum by weight of the blend andabout 5 to 95 percent hydroxyalkyl ether of guar gum. A sol of aparticular blend can be made by mixing the blend into water or. otheraqueous fluid with agitation and then allowing the sol to stand untilhydration of the components is complete. Hydration at room temperatureis usually complete after a few hours.

The rheological properties of aqueous sols made from blends ofxanthomonas gum and hydroxypropyl guar gum and from xanthomonas gum andhydroxypropyl guar gum alone are set out in detail in Tables 1 and 2.The sols used in obtaining the measurements shown in Tables 1 and 2 weremade according to the following procedure. Water in the amount of 495grams was agitated in a Waring Blendor at a speed required to form avortex one half the distance from the water surface to the blades. Tothe water being agitated was added 5.0 grams of a given blend orcomponent gum. This amount of blend produced sol containng l percentblend or component gum by weight. Stirring was continued for 30 secondsand the mixture was transferred to a 600 ml. beaker. After 4 hours, allthe sols had reached their maximum viscosity. The sols were allowed tostand an additional 16 hours to stabilize.

Viscosity measurements were made according to the following procedure.After a total of 20 hours, the viscosities of the blends containing 1percent blend of component gum by weight were then measured using aBrookfield LVT Viscometer equipped with a No. 3 spindle. The temperatureof all the samples was 25C.

After determining the viscosity of the 1 percent sols, a portion of eachsample was diluted to make samples containing 0.5 percent, 0.1 percentand 0.05 percent blend or component gum by weighct respectively. Theviscosities of the sols containing 0.5 percent and 0.1 percent blend orcomponent gum by weight were determined using a Brookfield LVTviscometer with a No. 3 spindle. The viscosities of the sols containing0.05 percent blend or gum were measured using a Brookfield LVTViscometer equipped with a UL Adaptor rotating at 6 rpm.

The gel strengths of the 1 percent sols were measured using a Model 35Farm VG viscometer according to the following procedure. The particularsol was agitated for 1 minute at 600 rpm. Agitation was stopped I andthe sol was kept in a quiescent state for 3 minutes. Agitation was againstarted at 3 rpm. and the maximum deflection on the dial was recorded.The dial reading was recorded in terms of pounds per square foot.

The flow rate of the sols was measured according to the followingprocedure. A Marsh Funnel having the dimensions 6 inches in diamter atthe top, 12 inches long, tapering to join a tube 2 inches long with athreesixtcenths inch inside diameter was used. The capacity of thefunnel was 1,500 ml. The discharge end of the funnel was closed with arubber cap. The sol was transferred to the funnel. The initial amount ofsol placed in the funnel was 450 grams. The funnel was placed over abeaker resting on the platform of a scale. The cap on the discharge endof the funnel was removed. A stop watch was started. The time requiredto discharge 300 grams and 350 grams of the sol was measured. The numberof seconds required to discharge the 50 grams of the sol between thedischarge of 300 grams and the discharge of 350 grams was calculated andrecorded as 3 grams per second.

30 70 33 0.55 20 8O 33 0 I00 Nil 0.62

Measurement not taken.

From the above data it can be readily seen the gel strengths exhibitedby the blends of xanthomonas gum and hydroxypropyl guar gum were higherthan those exhibited by the xanthomonas gum alone. Xanthomonas gum isitself unique among gum because of its relatively high gel stregnth.Yet, by blending it with hydroxypropyl guar gum, which has substantiallyno gel strength, even higher gel strenghts were obtained. Higher gelstrengths are beneficial in any application in which solid materials areto be suspended and stored in a thickened sol. Among such applicationsare thickening of paints, explosive materials and drilling muds. Lookingparticularly at the blend of 90 percent xanthomonas gum and 10 percenthydroxypropyl guar gum, increased gel strength was achieved without anyloss in flowability. Thickening compositions that contain about 70percent to 90 percent xanthomonas gum by weight and about 10 to 30percent hydroxypropyl guar gum produce sols having a combination of gelstrength and flowability which is peculiarly adapted to applications inwhich suspended material is to be stored in a thickened sol andeventually spread or pumped.

Using the viscosity measurement method described above the viscositiesof eight blends containing different proportions of xanthomonas gum andhydroxypropyl guar gum and two controls of xanthomonas gum andhydroxypropyl guar gum alone were measured. The samples contained theblends and individual gums at concentration levels of 1 percent, 0.5percent, 0.1 percent and 0.05 percent by weight. The shear force appliedto the sols were generated by viscometer speeds of 12, 30 and 60 rpm.The temperature was C. The results are shown in Table 2.

[Viscosity profile of sols containing thickeners] Percent by weightcomponent in blend:

Xanthomonas gum 100 90 10 70 60 50 40 20 0 Hydroxypropyl guar gum 0 1020 30 100 Viscoslty of 1% sols, oentlpolse rotatlon space:

1, S00 1, 700 1, 550 1, 500 1, 350 1,150 1, 050 8-50 650 350 800 700 720720 700 060 640 .560 400 300 60 r.p.m 420 420 420 410 410 390 380 350310 260 Vlscoslty of 0.17; sols, centlpolse rotation speed:

12 r.p.m 102 87 72 60 50 37 30 22 15 5 30 r.p.m 65 56 49 44 34 27 22 1511 5 60 r.p.m 42 38 33 29 24 20 17 14 11 6 Vlscoslty of 0.0571 sols,centlpolso rotation s UL adaptor: 6 r.p.m 21 21 17 16 14 12 9 8 5 3TABLE 1 Gel Strength and Flow Rates of Thickeners at 1% by weightConcentration Thickener Composition Percentage by Weight XanthomonasHydroxypropyl Gel Strength Flow Rate 5 Gum Guar lbs/100 ft. g./sec.

As showni n Table 2, blends of xanthomonas gum and hydroxypropyl guargum at a concentration level of 1 percent develop viscosities in a solgreater than the viscosities developed by xanthomonas gum alone. Blendshaving compositions between about 60 percent xanthomonas gum combinedwith 40 percent hydroxypropyl guar gum and I0 percent xanthomonas gumcombined with 90 percent hydroxypropyl guar gum have higher viscositiesthan hydroxypropyl guar gum alone when subjected to relatively low shearrates. At higher shear rates the viscosities of the sols containingblends decrease to about or below those of hydroxypropyl guar gum. Overthe entire blend composition range, the blends of xanthomonas gum andhydroxypropyl guar gum used at concentration levels of 1 percent byweight in the sol show more pronounced plastic characteristics andhigher viscosity differentials than either xanthomonas gum orhydroxypropyl guar gum alone.

Also apparent from the data shown in Table 2, the viscosities developedby the xanthomonas gum and hydroxypropyl guar gurn blend used atconcentration levels of 0.5 percent, 0.1 percent and 0.05 percent byweight of the sol were gradients between the high viscosities developedby xanthomonas gum used alone and the lower viscosities developed byhydroxypropyl guar gum used alone. The higher viscosities obtained fromblend concentrations of 1 percent by weight of the sol combined with thelower viscosities obtained at blend concentrations of 0.5 percent andbelow by weight of the sol, make the xanthomonas gum and hydroxypropylguar gum blends very useful in operationsv involving holding dissolvedmaterial in suspension, depositing the dissolved material and thenwashing away the sol. This type of operation is found in dyeing yarn forcarpets discussed in more detail below.

One of the industrial applications to which the thickener blends of thisinvention are particularly adapted is the dyeing of yarn for carpeting.There are basically two techniques for dyeing yarn for carpets. Onetechnique is to consecutively apply colors to short, preset lengths offiber yarn. The second technique is to knit a tubing of yarn, printcolors onto the yarn, then unknit the tubing andrewind the yarn. Thecontact of the yarn with the dye is so programmed as to produce apredetermined sequence of color application. Dyeing by either method ofhandling the yarn involves printing a coloronto the yarn using aprinting paste, fixing the color by steaming, washing away the pasteleaving the dye affixed to the yarn, drying, winding and packaging theyarn. The printing is accomplished by passing a roller over stands ofyarn or the knitted tube. The roller itself may either carry theprinting paste or push the yarn against a surface carying the printingpaste. In the case of individual strands of yarn being dyed, the

strands of yarn may be passed over a grooved roller carrying printingpaste in the grooves. Another roller operating in conjunction with thegrooved roller periodically pushes the strands of yarn into the groovesthus contacting it with the printing paste. ln the case of a knittedtube of yarn being dyed, the series of roller caryring printing pasteare passed over the tubing depositing the printing paste onto the yarn.Once the printing paste is deposited on the yarn, the color is set bysteaming. Steaming is usually conducted at temperatures between about210 and 214 F. After the color has been set, the paste carrying thecolor is washed away.

Natural and synthetic gums have been widely used as thickeners forprinting paste. The thickener holds the mark or color in the printingprocess. Once the paste is applied to the yarn, the thickner must allowthe dye to penetrate the yarn. Once the dye has penetrated the yarn, thethickneer must hold the printing paste to prevent migration of the dyeduring steaming. Finally, it is necessary that the gum can be washed outof the fabric leaving the dye affixed to the yarn. in brief, thethickener ideally has the following characteristics: (a) a low viscosityduring the rolling or printing operation to permit penetration of thecolor into the yarn, (b) high viscosity during steaming to preventmigration of the color, and (c) low viscosity upon dilution so that itcan be easily washed away. A comparison of these requirements with therheological character of blends of xanthomonas gum and hydroxypropylguar gum containing from about 10 to 60 percent xanthomonas gum byweight and about 90 to 40 percent hydroxypropyl guar gum by weight showthe following:

l. at concentrations of about 1 percent by weight the above blendsdisplay pronounced plastic properties producing low viscosities underhigh shear forces thus providing fluidity during the rolling colorpenetrating period, I

2. at concentrations of about 1 percent by weight the above blendsdisplay higher viscosities under low shear force than does xanthomonasgum alone thus more firmly holding the dye in place during dyeing andsteaming, and

3. at concentrations below about 0.75 percent by weight the blendshavesubstantially lower viscosities than xanthomonas gum thus allowingeasier removal by washing out by dilution than xanthomonas gum.

Blends of xanthomonas gums and hydroxypropyl guar gums provide anotheradvantage in dyeing yarn for carpet in" that the flow rate of theprinting paste can be controlled by the composition of the blend. Thepenetration of a sol into yarn can be changed at will by adjusting theratio of xanthomonas gum to hydroxypropyl guar gum in the blend. Theadjustability of the flow rate of printing paste is also important inthe flat printing of carpets. In this type of dyeing the yarn is alreadyattached to a backing. The printing paste is rolled over the carpetingand ideally penetrates the length of the yarn to the backing and nofurther. if the printing paste does not penetrate the length of yarn tothe backing, the yarn next to the backing is not dyed. If the priningpaste penetrates beyond the length of the yarn, it forms puddles on thebacking. Thus, the capability to adjuste the flow rate of the printingpaste in printing flat carpeting is very desirable. When carpets areprinted after the yarn has been affixed to the backing, the thickenerused in the printing paste is not washed out as in the yarn dyeingoperation. Therefore, thickeners with high gel strengths are essentialto avoid powdering off of the dye during dry handling or actual use. Asthe thickening compositions of the present invention exhibit unusuallyhigh gel strengths, they are peculiarly adapted to carpet printing.

Blends of xanthomonas gum and hydroxypropyl guar gum are compatible withanionic and nonionic dyes. Typical printing paste formulations includethe dye, preservatives, anti-foaming agents, thickener and water.Typically, the blends of the present invention are used in amounts ofabout 0.75 to 1.25 percent by weight of the printing paste formulation.

Another industrial application in which the blends of this invention areparticularly useful is in the making of explosive slurries. Explosiveslurries usually contain about 15 to 20 percent water, about 50 topercent explosive substance and a thickener. About 10 to 20 percentaluminum by weight of the slurry is usually added as a sensitizer. Theblends of the present invention provide higher gel strengths in solsthan can be obtained from natural or synthetic gums heretofore used tothicken explosive slurries. When the sols are cross linked to form gels,the gels are waterproof, nonpourable, pliable and non-brittle. Antimonyoxide and ammonia water, chromic nitrate, zirconyl sulfate and ammoniawater, potassium antimony tartrate and potassium dichromate are amongthe cross-linking agents that can be used to convert the sols to gels.Generally, the blends are used in amounts of about 0.7 to 1.5 percent byweight of the slurry.

Below is shown one typical explosive slurry formulation using axanthomonas gum hydroxypropyl guar gum blend and the same slurryformulation using xanthomonas gum and hydroxy-propyl guar gumindividually. The formulation is as follows:

Explosive Slurry Formulation Samples Components l ll lll parts partsparts Ammonium Nitrate 45 45 45 Sodium Nitrate 15 15 15 Water l9 l9 l9Xanthomonas Gum l 0.3 Hydroxypropyl Guar Gum l 0.7 Ammonium Perchlorate5 5 Aluminum Flakes l5 l5 Potassium Antimony 0.02 0.02 0.02 Tartrate(dry) Potassium Dichromate 0.01 0.01 0.01

(0.1 ml. of 10% solution) The above explosive slurry samples were mixedaccording to the following procedure. The sodium nitrate and water wereweighed into beakers. The mixtures were stirred until the sodium nitratewas substantially dissolved. To the nitrate solutions were added theammonium nitrate and the thickeners. After stirring the mixtures aboutfive minutes, the ammonium perchlorate was added followed by thealuminum and potassium antimony tartrate. Thirty minutes later 0.] ml.of a 10 percent by weight potassium dichromate solution was stirred intoeach mixture. After a period of 1 hour during which cross linkingoccurred, a portion of each slurry was immersed in water to determineits degree of waterproofness.

Sample I was very firm, rigid and nonpourable immediately afterpreparation. The portion immersed in water showed no disintegrationafter hours of immersion. The portion not immersed became dry, brittleand extremely cohesive.

Sample ll was soft and enlarged after 20 hours of immersion in water.These changes indicated it has absorbed water.

Sample lll after 20 hours immersion in water showed no indication ofdisintegration. The portion which had not been immersed was cohesive butsufficiently soft to be molded.

The thickeners of this invention exhibit many unique properties. Inaddition, the capacity to vary the composition of the blends toaccentuate desired properties provides a wide flexibility ofapplications.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A thickener blend comprising:

about 5 to 95 percent xanthomonas gum by weight of the thickener blend,said xant'homonas gum having the hydratability at 1 percentconcentration by weight of about 1,800 to 3,500 centipoise in water andin an aqueous solution containing 3 percent by weight potassiumhydroxide, and

about 5 to 95 hydroxyalkyl ether of guar gum by weight of the thickenerblend, said hydroxyalkyl ether of guar gum having a degree ofsubstitution of about 0.2 to 1.2 and wherein the alkyl group containsfrom two to four carbon atoms.

2. The thickener blend of claim 1 wherein the thickener blend comprisesabout 90 to 40 percent hydroxyalkyl ether of guar gum and about 10 to 60percent xanthomonas gum.

3. The thickener blend of claim 1 wherein the thickener blend comprisesabout 10 to 30 percent hydroxyalkyl ether of guar gum and about 90 topercent xanthomonas gum.

4. The thickener blend of claim 1 wherein the hydroxyalkyl ether of guargum is hydroxypropyl guar.

5. The thickener blend of claim 1 wherein said xanthomonas gum has thehydratability in water and aqueous solutions of 3 percent potassiumhydroxide by weight of about 2,000 to 3,000 centipoise.

w s UNITED STATES PATENT OFFICE CERTIFICATE OF COEClN 37 48201 July 21973 Patent No. Dated Inventor(s) Wesley A. Jordan It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

I V w Col 1, line 36, "betwen" should read --between-. Col 3, line 63,temperatures" should read "temperatures". 001 t, line 56, containng"should read "containing". 001 5, line t,

"weighct should read .--weight--. Table 2, line speee" should read--speed-; line 5, "5, 57'0 should read --567%O-.

line 9, "stregnth" should read --strength--. Col 7, line 34, "carying"should read --carrying--; line 41, "roller" should read --rollers--;line 5%, "thickneer" should read -thickener--. Col 8, line 28, "prining"should read --printing-; line 30, "adjuste" should read --adjust--. Col9, line 37, has should read --had--. Col 10, line 19, "5 to 95 shouldread ,----5% to Signed ahd sealed this 12th day of Fehruary 1-974.

(SEAL) Attest:

EDWARD MQFLETCHERJR. C. MARSHALL DANN Commissioner of Patents AttestingOfficer UNITED STATES PATENT OFFICE CERTIFICATE OF COEC'HQN 37 l82O1July 2A, 1973 Patent No. Dated Inventor-(s) Wesley A. Jordan It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Col 1, line 36, "becwen should read --between-. Col 3,

line 63, temperatures" should read --temperatures--. Col l, line 56,containng" should read --containing--. Col 5, line "weighct" should read"weight". Table 2, line 4, speee should read --speed-; line 5, "5,570"should read --567?O-.

o .9 line 9, "scregnch should read --str'ength-. Col 7, line 3 L,carying should read --carrying--; line 41, "roller" should read-rollers--; line 5 thickneer" should read -thick.ener--. Col 8, line 28,prining" should read -printing--; line 30, adjusce should read--adjust-. Col 9, line 37," has should read --had--. Col 10, line 19, "5to 95 should read --5% to Signed and sealed this IZthday of Fehruary 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Commissioner of Patents AttestingOfficer

2. The thickener blend of claim 1 wherein the thickener blend comprisesabout 90 to 40 percent hydroxyalkyl ether of guar gum and about 10 to 60percent xanthomonas gum.
 3. The thickener blend of claim 1 wherein thethickener blend comprises about 10 to 30 percent hydroxyalkyl ether ofguar gum and about 90 to 70 percent xanthomonas gum.
 4. The thickenerblend of claim 1 wherein the hydroxyalkyl ether of guar gum ishydroxypropyl guar.
 5. The thickener blend of claim 1 wherein saidxanthomonas gum has the hydratability in water and aqueous solutions of3 percent potassium hydroxide by weight of about 2,000 to 3,000centipoise.